In conventional drive apparatuses of this design having an external gearbox, the housing of the latter is connected rigidly to the rotor drum and forms one large mass mounted in free-floating fashion (see e.g. WO 2007/147893). Imbalances in the gearbox and the rotor then have an extremely disadvantageous effect on the rotor bearings, and are transmitted by them directly into the base for the centrifuge.
To avoid these disadvantages, attempts have therefore already been made to position the drum in elastically suspended bearings or in floating bearing assemblies. Such bearing mounts have not proven successful, however, since narrow gaps between the drum and its housing cannot be maintained, and resonant vibrations moreover occur at specific rotation speeds through which the drive transitions as it is shut off.
In a variant design, a separate gearbox bearing mount is additionally implemented in an independent bearing bracket; a free-floating gearbox having a long bearing shaft results, however, in imbalances on the gearbox side (see Stahl, Dekanterhandbuch [Decanter manual], vol. II, pp. 408-409).